Low-pressure steam heating system for vehicles



H. APPEL March 16, 1948.

LCM-PRESSURE STEAM HEATING SYSTEM FOR VEHICLES Filed Jan. 16, 1941 ,1fil /Mi" Hans 4pp M! I @L After-nay Patented Mar. .16, 1948 LOW-PRESSURESTEAM HEATING SYSTEM FOR VEHICLES Hans Appel, Prague, Germany; vested inthe Attorney General of the United States Application January 16, 1941,Serial No. 374,611 In Czechoslovakia December 24, 1938 2 Claims. 1

The present invention relates to a completely automatic, self-contained,low-pressure steam heating plant for vehicles.

-It is an object of this invention to provide a plant of the classdescribed having control means which interrupts combustion at apredetermined steam pressure in the boiler, which interruption, in turn,acts to lower the pressure. Such combustion control may comprise amembrane member which is operatively connected with the fuel and/or airsupply means to control said means.

The combustion control preferably operates in combination with waterreplenishing and associated steam releasing devices. The waterreplenishing device may comprise a float member and a water supply valveoperated thereby, and the associated pressure releasing device maycomprise a stand pipe connected to the water space of the boiler at thepoint oi the minimum permissible water level, which pipe releases theboiler pressure when the water level in the boiler reaches apredetermined minimum level. Where a relatively high boiler pressuremust be maintained, the stand pipe is also provided with a valve orclosure member controlled by the float device, which valve is opened assoon as the minimum permissible water level is reached to release thesteam pressure through the stand pipe.

The stand pipe closure member "allows said membrane, or pressuresensitive control member influencing the furnace, to maintain aregulated steam pressure in the boiler as long as the closure member isclosed and the wa er level in the boiler lies between the permissiblemaximum and minimum limits. In such an instance the steam pressure inthe boiler may be higher than the column 01' water in the stand-pipe.

It is another object of this invention to 'provide a low-pressure steamgenerating and heating plant for vehicles, saidplant being characterizedby great simplicity, reliability, and ease of operation.

To obtain these objects, a steam generating plant, automaticallycontrolled as far as the steam generation and the water supply areconcerned is used, not only to provide the radiators with heating steam,but to also simultaneously control the temperature of the heatingsurfaces of the radiators connected to the steam generating plant. Tothis end the radiators are so. connected to the steam space of theboiler of the steam generating plant that their interior spaces and thesteam space of the boiler form a closed space in which the same steampressure prevails at all places. Moreover, the above mentioned apv Fig.1.

paratus is provided at the boiler for automatically controlling thissteam pressure and thereby automatically controlling the temperature ofthe heating surfaces of the radiators connected'to the boiler. In thismanner special devices which hitherto were required for controlling thesteam supplied to the radiators and maintaining uniform the temperatureof the heating surfaces of the radiators are rendered superfluous.

In the accompanying drawings a heating system according to the invention01' example.

In these drawings:

Fig. 1 is a diagrammatic lay-out of a lowpressure steam heating plantaccording to the invention, and

Fig. 2 is a sectional view is shown by way of a detail shown in In theheating plant shown in Fig. 1 a'lowpressure steam boiler I, embedded inrefractory bricks, is mounted upon suitable beams of the vehicle, forinstance below the floor. At the elevation of the selected minimum waterlevel, a U-shaped stand-pipe I extends downwardly and then leads out 01'the water space of the boiler i and then upwardly above the water levelof water tank 24 mounted below the roof of the vehicle. A second pipe 4extends upwardly from the water space 01' the boiler and discharges intothe bottom of storage tank24 and forms part of a water feed pipe orreplenishing system for the boiler.

This pipe 4 is controlled by a closure member or piston 3 actuated by afloat 2 which, on reaching the maximum water level in the boiler I,closes the passage through pipe 4. Therefore, as long as the water isbelow the maximum level in the boiler and the prevailing pressurepermits, water will flow from the higher located tank 24 by way of thepipe 4 into the boiler i. Whenever the maximum water level is reached,pipe 4 is closed. Up to this time the diiference between the water levelin the highly located tank 24 and the water level in the boilerdetermines the pressure in the boiler. If the replenishing pipe 4 isclosed, the boiler pressure is determined by the column 01 water in thestand-pipe 5 as long as closure member 6, interposed in the pipe systemleading from the boiler by way of the-stand-pipe 5 into the atmosphereis open. a

The boiler I is heated with liquid fuel which is supplied from higherlocated fuel tank 25 to burner 29 by way of a pipe 21. The necessarycombustion air may be supplied by a blower H) which may be electricallydriven and connected to the burner 29 by the pipe bend shown.

' boiler I.

The steam space of the boiler I is connected, by means of the pipes lI,I8, to the radiators I9 which, when the inlet valves are opened by thesetting levers 2 I, are all filled with steam ofthe same pressure asthat of the boiler, whereby the temperature of their heating surfaces ismaintained corresponding to the steam pressure controlled by the heightof stand-pipe 5.

With a larger number of radiators the pressure limited by the water inthe stand-pipe is not sumcient. For this'purpose a closure member 8, i.e. a piston, is arranged in the pipe system leading to the stand-pipe]from the boiler I which piston is connected to the closure member 3 insuch a manner that on reaching the predetermined minimum water level inthe boiler piston I closes the passage to the stand-pipe 5.

When the heating system is in operation, piston 4 closes the passageleading from the boiler by way of the stand pipe I! into the atmosphereand a bellows I4, filled for instance with glycerine, is provided toregulate the steam pressure in the On being compressed, bellows I4 feedsglycerine by way of pipe I3 to a spring loaded piston in cylinder I2which is moved thereby and swings a lever I4? In Fig. 2 of the drawingsthe cylinder I2 and the lever II are shownin detail and in section andside elevation respectively. By this arrangement the burner is socontrolled and the firing or the boiler I is so influenced that apredetermined pressure is maintained in the boiler which assures thesupply of all radiators connected to the boiler with steam.

In the stand-pipe I a throttling memberJI, for instance in the form of ahelically wound small tube, not shown in the drawings, may be insertedwhich ofl'ers less resistance to the passage of steam than to thepassage of water. It the pressure in the boiler rises while the passageto the atmosphere by way of the stand-pipe 5 is open, that is, while thepiston 8 is drawn upwardly, water may be forced up through thestand-pipe I and into tank 24. If the water level in the boiler I isdropped to a predetermined minimum, steam only is discharged throughstand-pipe I and nearly no resistance is caused by the throttling member22 to the passage of this steam, so that atmospheric pressure is quicklyreached. and the re-fllling operation with water from the higher locatedtank into the boiler isinitiatedas'follows: I

The drop of the water level causes a drop of the float 2 and thereby anopening of valves 3 and 4 and flow of water from the tank 24 by way ofthe pipe 4 into the boiler I whereby the development of steam in theboiler is reduced which accelerates the refilling operation.

If the permissible maximum water level is reached, the closure members 3and 8 are closed again and the steam pressure in the boiler rises. Assoon as this pressure has reached a predetermined value, the supply offuel oil to the burner is interrupted by the pressure control member I4acting by way of the piston arranged in the cylinder I2 and the leverI8. In this manner the required in the passage leading from the boilerby way of the stand-pipe 5 into the atmosphere and the pressure in theboiler and in the radiators is controlled by the column of water in thestandpipe 5, whereby for assisting this pressure regulation a controldevice for the fuel may be provided in the form of a bellows ordiaphragm box I4 which influences the burner 29. The regulatingoperations are eflected as follows:

If the boiler pressure has reached a predeter- ,mined value the supplyof oil to the burner is interrupted by the pressure control I4, I2, andI8, the burner, however, continuing to burn for several seconds. In thismoment the water pressing upwardly in the stand-pipe 8 overcomes theresistance of the throttling member 22, and water flows into the tank24. The float 2 drops. Thereby, in the manner already described, wateris discharged from the tank 24 into the boiler, the pressure drops. thecontrolI4, I 2 and I8 again effects opening of the fuel supply and theburner 29 is ignited by a pilot flame. If the water level in the boilerI'drops below the predetermined minimum value, 1. e. below the top a: ofthe leg of the standpipe I inside the boiler, then, after pressing ofthe water out of this tube into the tank 24, steam flows into theatmosphere above the tank, whereby the pressure in the boiler quicklydrops and water speeds into the boiler through conduit 4., If the boilershould exceed the highest permissible limit, a safety valve 33 is openedwhich is provided in the steam main 3i leadingtothe radiators I 8.

I To increase the reliability of the heating plant which depends on asufllcient quantity of water always being available in the higherlocated tank 24, condensed water from the radiators I9 is conpressure inthe boiler I and in the radiators I9 connected thereto is regulated bythe pressure ducted to a collecting tank I5, and pumped by means of pumpII through conduits 36 and 35 into tank 24. i

A closure member 9 is mounted in the steam main 3| for centrally closingor disconnecting all radiators I I. For further safety a drain valve 1at the bottom of the boiler I, and an outlet valve 8 arranged at thelowest point of the water return feeding pipe system 2! may be provided.The flow of water from the tank 24 may be diverted by manipulating 2-wayvalve 23 provided in the boiler feed pipe system 4, if it is intended tohave this water available for other purposes.

As it sometimes happ ns that the vehicle provided with this heatingplant is to be arranged in a train which is drawn by a steam locomotivesupplying the heating devices oi all cars with steam, the closure memberS is constructed as a two-way valve in such a manner, that this valve 9,when closing steam pipe 3i towards the boiler I, connects the radiatorsI9 by way of a branch pipe 32 to a pipe 30 located below the vehicle andto the main steam pipe of the train.

What is claimed is:

1. A low pressure steam heating system for vehicles. comprising, incombination. a small water capacity steam boiler disposed on thevehicle, radiators, a steam main interconnecting said boiler and saidradiators, an automatic heat supply mechanism connected with said boilerfor supplying heat thereto and including boiler pressure responsivemeans controlling the heat supply in accordance with the boilerpressure, a feed water storage tank located in the vehicle above theelevation of said boiler, a conduit connecting the water space or saidtank with the water space of said boiler, valve means in said conduit,water level responsive means connected with said boiler acamva and withsaid valve means and opening said valve means when the water level insaid boiler has reached a predetermined minimum and closing said valvemeans when the water level in said boiler has reached a predeterminedmaximum, and a U-shaped stand pipe having a shorter branch extendingfrom the bottom of the boiler upwardly in the water space of the boilerto the minimum permissible water level, and a longer branch extendingfrom the bottom of the boiler to a level in the storage tank above thewater level in said tank. l

2. A low pressure steam heating system for vehicles, comprising, incombination, a small water capacity steam boiler disposed on thevehicle, ragiators, a steam main interconnecting said boiler and saidradiators, an automatic heat supply inechanism connected with saidboiler for sup- !{Jlying heat thereto and including boiler pressureresponsive means controlling the heat supply in accordance with theboiler pressure, a feed water storage tank located in the vehicle abovethe elevation of said boiler, a conduit connecting the water space ofsaid tank with the water space of said boiler, valve means in saidconduit, water level responsive means connected with said boiler andwith said valve means and opening said valve means when the water levelin said boiler has reached a predetermined minimum and closing saidvalve means when the water level in said boiler has reached apredetermined maximum, a

one of its arms located outside said boiler and above the elevation ofthe water level in said tank, the end of the other arm of said U-shapedstand pipe communicating with the interior of the boiler at a pointsubstantially coinciding with said predetermined minimum water level,and valve means disposed in said stand pipe and being operativelyconnected with said water level responsive means and being opened whenthe water level falls below a predetermined minimum and being closedwhen the water level rises above the predetermined minimum elevation,the conduit, stand pipe, their respective valves and the water levelresponsive means being so designed and related that when the water levelin the boiler reaches its predetermined minimum both the conduit and thestand pipe are opened, so that water can flow from the tank to theboiler through the conduit, and from the boiler to the tank through thestand pipe.

U-shaped stand pipe connected with the water space or said boiler andhaving the upper end of HANS APPEL.

REFERENCES crrnn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,125,839 Wasson et a1 Aug. 2,1938 2,162,337 Kriechbaum June 13, 1939 2,103,178 Raymond Dec. 21, 1937315,160 Pentecost Apr. 7, 1885 41,504 Hammond Feb. 9, 1864

